1. Field of the Invention
The present invention relates to an indicator for indicating a relative position of two components that are displaceable relative to one another, a measuring apparatus comprising such position indicator and a method of manufacturing an indicator pattern.
2. Brief Description of Related Art
FIG. 1 shows a conventional caliper gauge for determining geometric dimensions of physical objects. Caliper gauge 1 comprises two components 3, 5 which are linearly displaceable relative to one another. Each component 3, 5 has one measuring leg 7, 9, respectively, which can be brought to rest on the object to be measured. The two components 3 and 5 bear indicator patterns 11, 13, respectively, which are conventionally termed scale or Nonius (vernier).
The first indicator pattern 11 of component 3, the scale, comprises a plurality of partial patterns 4, all of which are configured as markings and are spaced a distance of 1 mm apart from one another in a direction of displacement of the two components 3 and 5, i.e. recur in a periodic or regular pattern. In particular, over a length L1 of 20 mm N1=20 of such partial patterns 4, or partial markings, respectively, are disposed such that a distance between two partial patterns 4 is 1 mm. The indicator pattern 13, the Nonius, comprises N2=20 partial patterns 6, which are regularly spaced over a length L2=19 mm. Such a 19/20-Nonius allows an accuracy of reading of1 mm−19/20 mm=0.05 mm.
When reading the caliper gauge, the zero mark of the Nonius 13 is regarded as the decimal point. Left of the zero mark, the full millimeters are read off the scale 11. Subsequently, that partial mark 6 to the right of the zero mark of the Nonius 13 is selected that substantially aligns with partial mark 4 of scale 11. The number of partial marks 6 on the Nonius 13 between its zero mark and the aligned mark indicates the number of 1/20 millimeters behind the decimal point.
Those caliper gauges have, however, turned out to have a limited accuracy of reading. Furthermore, the caliper gauge described above is only suitable for measurement of linear, geometric distances.